Rolling mill for producing annular shapes

ABSTRACT

A ROLLING MILL FOR PRODUCING ANNULAR SHAPES INCLUDES A ROLLER ROTATABLY MOUNTED IN THE ROLLING MILL FRAME AND A ROLLING MANDREL ASSOCIATED WITH THE ROLLER WHICH IS ROTATABLY MOUNTED AT EACH END. THE MANDREL CAN BE FED TOWARD AND AWAY FROM THE ROLLER AND IT INCLUDES ONE BEARING WHICH MAY BE CONNECTED TO OR REMOVED FROM THE ROLLING MANDREL TO FACILITATE THE LOADING AND UNLOADING OF THE WORKPIECE. BOTH OF THE ROLLING MANDREL BEARINGS ARE PIVOTAL IN A PLANE DEFINED BY THE CENTER LINES OF THE ROLLER AND THE ROLLING PLANE DEFINED BY THE CENTER LINES OF THE ROLLING MANDREL BEARINGS IS ADJUSTABLE IN RESPECT TO ITS SPACING AWAY FROM THE ROLLER AND INDEPENDENTLY OF THE FEEDING MOTION OF THE ROLLING MANDREL IN RESPECT TO THE ROLLER.

- 1971 J.JEUKEN ROLLING mm. FOR rnonucxne ANNULAR SHAPES Filed Aug. 19. 1969 2 Sheets-Sheet 2 Fig. 3

Fig. 4

INVENTOR.

' was E'PH av JED/(EN 7151M MW 4 r1072 ME VS United States Patent ROLLING MILL FOR PRODUCING ANN ULAR SHAPES Joseph Jeuken, Holzwickede, Germany, assignor to Rheinstalll Wagner Werkzeugmaschinenfabrik m.b.H., Dortmund, Germany Filed Aug. 19, 1969, Ser. No. 851,274

Claims priority, application Germany, Oct. 2, 1968,

P 18 00 569.1 Int. Cl. B21b N US. Cl. 72101 6 Claims ABSTRACT OF THE DISCLOSURE A rolling mill for producing annular shapes includes a roller rotatably mounted in the rolling mill frame and a rolling mandrel associated with the roller which is rotatably mounted at each end. The mandrel can be fed toward and away from the roller and it includes one hearing which may be connected to or removed from the rolling mandrel to facilitate the loading and unloading of the workpiece. Both of the rolling mandrel bearings are pivotal in a plane defined by the center lines of the roller and the rolling mandrel and at least one of the rolling mandrel bearings is adjustable in respect to its spacing away from the roller and independently of the feeding motion of the rolling mandrel in respect to the roller.

SUMMARY OF THE INVENTION This invenion relates in general to the construction of rolling mills and in particular to a new and useful rolling mill for producing annular shapes and which includes a roller rotatably mounted in a frame of a rolling mill and a rolling mandrel which can be fed toward the roller and is rotatably mounted at each of its ends.

In rolling mills which are adapted to produce annular shapes the rolling mandrel is cantilevered, that is, it is mounted at one end and the annular blank is placed over the free end for working and after finishing it is removed. During the actual rolling Operation the free end is also supported in order to keep the bending stresses as small as possible. The mandrel must be kept as thin as possible in consideration of the material loss caused by punching the hole through the annular blank. Pivotable or vertically movable counterbearings'are used to support the free end of the mandrel and they are mounted to the carriage which feeds the rolling mandrel. The mobility requirements for the counterbearings means that it is not possible to support the pre rolling end of the mandrel in a manner equivalent tothe mounting of the other end in respect to resiliency. The consequence thereof is that the free end of the rolling mandrel is pushed away from the roller, under the influence of the rolling force and the rolling gap formed by the working surfaces of the roller and rolling mandrel, and this is true in spite of the camber of the rolling mandrel which is provided to compensate for the deflection of the mandrel so that it will not stay parallel. This results in deviations from the desired ring-shaped formation of the workpiece and greatly adds to the cost of machining the workpiece particularly when manufacturing rings or very expensive and hard to machine materials such as titanium.

Attempts to avoid the disadvantages mentioned above include the compensation for the deformations which are brought about by the rolling forces by the use of additional shape correctionsof the rolling surfaces or of the rolling mandrel and the roller. Such a design change can take into consideration only a certain specific case resulting from axial ring width and rolling force. It is for this reason that the method does not lead to satisfactory shape accuracy of the rolled rings, especially where rolling mills for annular shapes are involved. Such mills should be universally applicable to roll rings of the most varied dimensions and materials, especially when they are laid out for large axial ring widths and great rolling forces.

In the known rolling mills, the rolling mandrel is considered in terms of stress analysis as a beam which is fixed at one end and which has a free end which is additionally supported during the rolling operation. The greatest bending moment occurs in the area of the clamping point where the replaceable rolling mandrel is inserted in the bushing receiving it. The bearing loads of the bearings effecting the clamping are very high. The unfavorable stress imposed on the rolling mandrel increases the danger of its cracking. The great bearing loads and the moments stemming therefrom require considerable structural expenditure to make the feeding carriage for the rolling mandrel stiff enough. In addition, very big and expensive bearings with large diameters are necessary and they require a correspondingly large roller diameter and, hence, high tool costs, especially for rolling thinwalled rings. The adjustability of the rolling mandrel by pre-loading which is advantageous from the standpoint of load variation and ring profile change considerations and for adjusting a non-parallel rolling gap will lead, depending on the orientation of the preload, to a substantial additional increase in the loads imposed on the bearings, rolling mandrel and carriage. The force distribution over the various parts cannot be calculated reliable for the various operating conditions. Therefore, the advantage of preloadability of the rolling mandrel must be achieved by a cost considerably more than the rolling mill.

In accordance with the invention, it is possible to roll rings of greatly varying axial width with greatly varying rolling force while maintaining excellent shape accuracy of the ring profile. In addition, the construction makes it possible to adjust for deviations in the parallel positioning of the mandrel and the parallel arrangement of the rolling gap and to operate at substantially reduced maximum loads on the critical points of the rolling mandrel, the rolling mandrel bearings and the rolling mandrel carriage in comparison to the known rolling mills for annular shapes. Because of the reduction of the maximum load imposed on the rolling mandrel bearings it is possible' to use smaller and cheaper bearings and in addition, the distances between the rolling mandrel and the roller can be reduced. This makes the diameter of the roller, the length of the rolling mandrel counter bearing, and also the entire rolling mill smaller so that both weight and cost are saved. The maximum bending of the rolling mandrel is no longer located where the rolling mandrel is inserted in its chucking bushing and Where the effects of notching and other strength-reducing influences cannot be avoided. This increases operational safety and decreases tool costs. Finally, the clearly defined actions of the forces enable a further reduction in the cost of the design due to the fact that the mathematical safety allowances can be lowered.

In accordance with the invention the rolling mill for annular shapes includes a roller rotatably mounted in the rolling mill frame and a rolling mandrel which can be fed toward the roller and is rotatably mounted at both ends. One of the bearings for the rolling mandrel is removable from the mandrel for the purpose of loading and unloading the workpiece. Both rolling mandrel bearings are pivotal in the plane defined by the centerlines of the roller and rolling mandrel and at least one of the rolling mandrel bearings is adjustable in respect to its spacing from the roller and independently of the feeding motion of the rolling mandrel. The pivotability of the rolling mandrel bearings makes it possible to consider the rolling mandrel as a beam which is fixed at both ends in terms of stress analysis. When the rolling mandrel is stressed symmetrically by the rolling force, both bearings are loaded uniformly. When the stress is asymmetrical, the sum of all radial bearing forces equals the total rolling force. Additional bearing forces due to the chucking moment of the rolling mandrel and due to the preloading moment no longer occur. Because the rolling mandrel is not chucked it is true that the deflection of the rolling mandrel under the same rolling force becomes greater in the area between the rolling mandrel bearing than when the rolling mandrel is chucked in the usual prior art manner; but this can readily be compensated for by appropriately cambering the rolling mandrel. The pivotability of the rolling mandrel bearings may be achieved by the known means of bearing technology such as by bearings with spherical supports for the race surfaces or the like.

A design particularly favorable with regard to hearing diameters, and hence total cost, results from making in accordance with the invention the bearing housings of the rolling mandrel bearings pivotable about respective axes each of which is perpendicular to the plane defined by the centerlines of the roller and the rolling mandrel. When the rolling mandrel is stressed asymmetrically, for example when rings are formed with axial widths smaller than the biggest possible in a rolling mill, the unremovable rolling mandrel hearing, which also must absorb the forces acting in axial directions upon the rolling mandrel, is stressed by a greater radial force than the removable rolling mandrel bearing. It is often advantageous, according to a further suggestion and in order to be able to utilize the bearings to their utmost even under changing rolling programs and yet to obtain approximately the same life for all bearings, to make only the bearing housing of the non-removable rolling mandrel bearing pivotable about an axis perpendicular to the plane defined by the centerlines of the roller and the rolling mandrel. The removable rolling mandrel bearing is made pivotable by means of a self-aligning roller bearing or the like.

The movability of the one rolling mandrel bearing independently of the feeding motion of the rolling mandrel may be effected by known means such as a key or spline motion, a cam motion, threaded spindle or the like. A particularly simple and conveniently operable and inexpensive solution is proposed by the invention for the rolling mill which includes a counterbearing arm for the removable rolling mandrel bearing which is pivotable about an axis of the carriage which effects the feed-in motion of the rolling mandrel. The pivoting axis is made adjustable by means of adjustable cams.

Accordingly it is an object of the invention to provide an improved rolling mandrel for forming annular shapes which includes a rotatable roller mounted in the rolling mill frame and a rolling mandrel which is rotatably mounted on both ends which is carried on a carriage and which is movable relatively to the roller, and wherein both rolling mandrel bearings are pivotal in a plane defined by the centerlines of the roller and the rolling mandrel and wherein at least one of the bearings for the rolling mandrel is adjustable in respect to its spacing from the roller and independently of the feeding motion of the rolling mandrel.

A further object of the invention is to provide a rolling mill for producing annular shapes which is simple in design, rugged in construction and economical to manufacture.

The various features of novelty which characterizes the invention are pointed out with particularly in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects obtained by its uses, reference should be had to the accompanying drawings, and descriptive matter in which there is illustrated a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a partial side elevational view and partial sectional view taken along the line 1-1 of FIG. 3 of a rolling mill for annular shapes constructed in accordance with the invention;

FIG. 2 is a section taken along the line 22 of FIG. 1;

FIG. 3 is a section taken along the line 33 of FIG. 1, the cam position being indicated offset for better clarification in comparison to FIG. 1; and

FIG. 4 is a section taken along the line 44 of FIG. 1.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein comprises a rolling mill which includes a rolling mill frame 1 on which is rotatably mounted a cylindrical roller or main roll roller 2 for rotation about a substantially vertical axis 3. A carriage 4 for mounting and feeding a rolling mandrel 5 is mounted for movement relative to the frame 1 under the control of a piston and cylinder combination which includes a piston 6 which is attached to the rolling mill frame 1 and a cylinder 7 attached to the carriage 4. Separate additional piston and cylinder combinations (not shown) may be provided for elfecting the axial movement relative to the frame 1 if so desired.

In accordance with the invention the mandrel 5 is mounted at its one end in bearings contained in a bearing housing 14 which is movable with the carriage 4 and it is adjustably rotatably supported in self-aligning bearings 20 carried at one end of a pivotal arm '21 which is also movable with the carriage 4. The mandrel 5 may be mounted for rotation about an axis 8. It includes a lower end 9 which is inserted into a chucking sleeve 10 and is connected to the sleeve by a screw 11. The bearing housing 14 contains radial bearings 12 and a thrust bearing 13 for rotatably supporting a chucking sleeve 10 therein. In accordance with a feature of the invention the bearing housing 14 is mounted on pins 15 and 16 which extend outwardly from each side and rotatably support the bearing housing 14 for small pivotal movement on the movable carriage 4.

In accordance with a further feature of the invention an upper conical end 18 of the rolling mandrel 5 is inserted into a removable bearing sleeve 19 carried on the arm 21 and which is rotatably guided by the self-aligning roller bearing 20. The arm 21 is bifurcated and includes two arm portions which are pivotally mounted on respective cam discs 23 and 24 for pivotal movement about an axis 22. The cam discs 23 and 24 are carried at respective ends of a shaft 25 which is rotatably mounted on supporting pedestals or ways 26 and 27 of the carriage 4. The shaft 25 may be rotated by a driving motor which drives through a worm 50, a pinion 52 and a drive gear 28 to a gear afiixed to the shaft 25 for the purpose of changing the eccentric position of the cams 23 and 24 for providing a slight axial shift of the upper end of the mandrel 5. A workpiece ring 29 is positioned over the mandrel 5 after the arm 21 is pivoted upwardly and it rests on a workpiece rolling table 30 during the shaping thereof.

The operation of the device is as follows:

For loading a ring blank or workpiece 29 over the mandrel 5; the carriage 4 is moved to the right in respect to the position indicated at FIG. 1. A pivoting mechanism (not shown) moves the arm 21 upwardly to remove the bearing 20 from the upper end 19 of the mandrel. In that position of the carriage 4 the pivotability of the bearing housing 14 about the axis 17 is so limited that the ring blank can be pushed over the rolling mandrel 5 without difficulty. Thereafter it is possible to place the bearing sleeve 19 onto the upper conical end 18 of the rolling mandrel 5 by flipping the arm 21 downwardly. After the arm 21 is flipped downwardly the carriage '4 is moved to the left by actuating the piston 6 in respect to its associated cylinder 7. A power train is therefore established between the revolving roller 2 which has a shaft 2a which is driven by means (not shown), the ring or workpiece 29 and the rolling mandrel 5 so that the rolling operation begins. If the rolling mandrel 5 is stressed symmetrically by the rolling force the radial bearings 12 and the self-aligning roller bearings 20 suffer identical radial stresses. The bearing housing 14 and the self-aligning roller bearing 20 adjust in accordance with the deflection of the rolling mandrel 5. For rolling cylindrical rings the rolling mandrel 5 is so shaped that under the stress occurring most frequently, the generatrix of the rolling mandrel facing the roller 2 remains straight and parallel when the cam discs 23 and 24 are set appropriately with respect to the opposing generatrix of the roller 2. When rolling lower rings, the rolling mandrel 5 is stressed asymmetrically so that the radial bearings 12 are stressed more than the self-aligning roller bearing 20. This condition is taken into consideration by designing radial bearings 12 so that they have a longer theoretical life.

The consequence of stressing the roller mandrel 5 asymmetrically is a bending line of the rolling mandrel which is modified as compared to asymmetrical stressing. In order to keep errors in the shape of the rolled ring which stem therefrom as small as possible the geometrically elfective life of the counterbearing arm 21, that is the distance of the self-aligning roller bearing 20 from shaft 25, can be so changed by appropriately setting the cam discs 23 and 24 that a nearly parallel rolling gap between the roller and the rolling mandrel is effected. This change is effected through the drive system for rotating the shaft 25. Even when it is intended to roll slightly conical rings without changing the rollers, for eX- ample to counteract the tendency of the rings to climb during the rolling operation, or when shape corrections are to be made which may have become necessary during the rolling operation; it is also possible to effect this by appropriately turning the cam discs 23 and 24 by means of their drive mechanism 50, 52, 28, and 54.

What is claimed is:

1. A rolling mill for annular shapes, comprising a frame, a roller rotatably mounted on said frame, a carriage movable relative to the axis of said roller, a rotatable mandrel carried on said carriage, first bearing means for said mandrel on said carriage for rotatably supporting one end of said mandrel, second bearing means on said carriage for rotatably supporting the other end of said mandrel, means mounting said first and second bearing means for pivotal movement in the plane defined by the axes of said roller and said mandrel and means mounting at least one of said first and second bearings for adjustable movement in respect to its spacing from said roller, said mounting means comprising first and second bearing housings each being pivotal about an axis perpendicular to the plane defined by the axes of said roller and said rolling mandrel.

2. A rolling mill according to claim 1 wherein said mounting means comprises a first bearing housing carried in a fixed position on said carriage, axle means pivotally supporting said first bearing housing for pivotal movement about an axis extending substantially perpendicular to the plane defined by the axes of said roller and said roller mandrel.

3. A rolling mill according to claim 1 wherein said mounting means includes first bearing means carried by said carriage at a fixed location and second roller means, a counterbearing arm pivotally mounted on said carriage and carrying said second bearing means at its free end thereof, said counterbearing arm being movable upwardly with said second bearing means to open one end of said mandrel for receiving a workpiece thereover, and means for shifting said counterbearing arm for adjusting the position of said second bearing means relative to said roller.

4. A rolling mill for annular shapes comprising a fixed frame, a roller rotatably mounted on said frame, a carriage movable on said frame relative to said roller, first bearing means on said carriage, a mandrel engaged in said first bearing means for rotation about an axis substantially parallel to the axis of rotation of said roller, an arm having one end pivoted on said carriage and an opposite end overlying the free end of said mandrel, second bearing means on said arm engageable with said mandrel for rotatably supporting this end of said mandrel, and means for mounting said arm on said carriage permitting movement of said second bearing means relative to the axis of said roller.

5. A rolling mill according to claim 4 including means pivotally mounting said first bearing means for a pivotal movement about an axis substantially perpendicular to the axis of said roller.

6. A rolling mill according to claim 5 wherein said means for mounting said arm for movement to shift said second bearing means comprises an eccentric disc, said arm having a hub portion engaged around said eccentric disc, and shaft means connected to said disc for rotating said disc to shift said hub portion and said arm laterally.

References Cited UNITED STATES PATENTS 835,505 11/1906 Ehrhardt 72101 838,570 12/1906 Numan 72-101 1,429,502 9/1922 Goldberg 72-10l 1,832,881 11/1931 TaylOl' 72111 2,605,809 8/1952 Olvey et al. 72101 MILTON S. MEHR, Primary Examiner US. Cl. X.R. 72111 

